Individuals engaged in many different types of activities above the ground use ropes or safety lines to secure and protect themselves from a fall. Such activities may include utility workers working atop poles or other equipment; firefighters or other rescue personnel working atop or alongside a building; and construction workers working on tall buildings. The use of safety lines is not limited to work applications. The safety of various recreational activities is dramatically increased by the use of ropes or safety lines. These activities include, for example, rock climbing and spelunking. In addition, hunters who hunt from elevated platforms also can benefit from the use of safety ropes.
A rope alone, however, does not provide a complete solution. The rope should be secured to the person in a manner that allows the person to adjust his position on the rope (such as by when climbing or descending) but still protects the person from a fall. A variety of devices to provide fall protection have been developed, which typically operate as follows. A rope threads through the device, and the device is securely attached to a harness worn by a person with a carabineer. The rope slides through the device so long as the rope is relatively slack. Tension upon the rope usually causes a movable cam in the device to rotate into a position that binds the rope and thereby halts the passage of the rope through the device. If the tension is caused by a person falling, the device jams the rope and arrests the fall.
Some devices also include a lever attached to the cam that can be used to open the cam and release the rope. With the cam in open position on such devices, however, there is no appreciable friction on the rope, such that the rate of descent is quite rapid. If the operator were to panic and hold the lever such that the cam in the open position while descending, the rapid rate of descent could result in injury.
Another shortcoming of existing devices is that they cannot be operated remotely. If a person were to become unconscious and fall, or become unconscious as a result of the fall, or otherwise be injured such that he could not operate the device, his fall may be arrested. However, it may be impossible to lower him in a controlled manner without requiring a rescuer to go to the same perilous situation as the incapacitated person.
Thus, there exists a need for a safety device that provides automatic fall arrest, but allows for a safe, maximum rate of descent as an anti-panic feature. It would be further advantageous if such a device could be operated by remotely.